Using Oxide-Trap Charge-Pumping method in radiation reliability analysis of short lightly doped drain transistor

摘要

A thorough investigation of the possibility of application of Oxide-Trap Charge-Pumping (OTCP) extraction method to evaluate the radiation-induced traps in short LDD-transistors is conducted. We have successfully demonstrated that the OTCP is able not only to determine all kind of traps induced by radiation in narrow LDD-transistors, but also in short LDD-transistors. Firstly, we have presented a methodical approach to take out the LDD effect from charge pumping curves, leaving only the effective channel length charge pumping. Secondly, we have extracted the radiation-induced interface-, oxide, and border-trap for LDD-NMOSFET and LDD-PMOSFET with varied gate length and fixed gate width. Finally, we have performed a comparison between OTCP and Sub-Threshold Slop (STS), Mid-Gap (MG), Dual-Transistor Charge-Pumping (DTCP), and Dual-Transistor Border-trap (DTBT). OTCP method shows perfect agreement with all methods regarding oxide-trap (ΔNot) extraction versus gate length. However, it does not correlate with STS and MG for interface-trap (ΔNit), because the last methods overestimate ΔNit by sensing border-trap (ΔNbt) like interface-trap. We have observed the same behaviors in the narrow LDD-transistors.